A. Field of the Invention
The invention relates to electric switches and, more particularly, to polarity reversing electric switches.
B. Prior Art
Electric switches are used to interrupt power flow to a circuit, and to switch power from one portion of a circuit to another. Various characteristics of such switches, such as cost, size, reliability, and power handling capacity, among others, are dependent on the particular application for which the switches are used. The present invention is directed to low cost, mass produced switches with a moderate current capacity and used for applications such as energizing circuits, e.g., electric motor circuits, in automobiles and the like, and the prior art will thus be described with particular reference thereto.
Exemplary of the prior art in these applications are U.S. Pat. No. 3,671,693 issued June 20, 1972 to Guy M. Farrell; U.S. Pat. No. 3,746,809 issued July 17, 1973, to Martin Gaber; U.S. Pat. No. 3,601,568 issued Aug. 24, 1971 to Wesley T. Sorenson; U.S. Pat. No. 3,403,237 issued Sept. 24, 1968 to R. D. Wysong; and U.S. Pat. No. 3,519,775 issued July 7, 1970 to F. J. Weremey. These illustrate primarily single pole, double throw switches which utilize three terminals, namely, a common terminal and two switched terminals. As illustrated in the patent to Wysong, however, a pair of these switches may be utilized together to form a double pole, double throw switch; such a switch has six terminals, namely two common terminals and two pairs of switched terminals.
In forming a polarity reversing switch, the present practice is to utilize a double pole, double throw; six terminal configuration and wire alternate ones of the switched terminals together in the switch housing. This wiring or busing can constitute a significant part of the cost of manufacturing the switch, particularly where the switch is used in a large volume, low cost application such as the auto industry. Further, each additional element, such as a terminal, that is used in the switch increases not only the materials cost, but the cost of assembly as well and the latter element of cost is frequently a significant portion of the cost of manufacturing the switch. Thus, quantitatively small savings in materials or assembly, or both, can be significant in producing a more competitively priced switch.